Humeral Head Implant System

ABSTRACT

A humeral head implant system includes a head component including a first articulating surface, a second bottom surface extending from the first spherical articulating surface, a first cavity extending a first distance into the head component from the second bottom surface, and a second cavity extending into the head component along a cavity axis. The head component defines a head axis extending through a center of the first articulating surface parallel to the cavity axis. A base component defines a slot extending from a first width to a second width. An insert component includes an insert body, a first engagement feature, and a slot engagement feature. The first engagement feature is received in the second cavity along the cavity axis. The insert body has an insert thickness less than the first distance, and the slot engagement feature slides into the slot in a direction transverse to the cavity axis.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 16/531,885, filed on Aug. 5, 2019, which is a continuation ofU.S. Pat. No. 10,368,999, filed Aug. 24, 2017, which claims the benefitof and priority to U.S. Provisional Application No. 62/378,963, titled“ROTATOR CUFF SPARING DEVICES AND METHODS,” filed Aug. 24, 2016, U.S.Provisional Application No. 62,419,905, titled “HUMERAL HEAD IMPLANTSYSTEM,” filed Nov. 9, 2016, U.S. Provisional Application No.62/469,425, titled “HUMERAL HEAD IMPLANT SYSTEM,” filed Mar. 9, 2017,U.S. Provisional Application No. 62/463,448, titled “METHOD OFPERFORMING POSTERIOR ROTATOR CUFF SPARING TOTAL SHOULDER ARTHROPLASTY,”filed Feb. 24, 2017, and U.S. Provisional Application No. 62/531,721,titled “METHOD OF PERFORMING POSTERIOR ROTATOR CUFF SPARING TOTALSHOULDER ARTHROPLASTY,” filed Jul. 12, 2017, the disclosures of whichare incorporated herein in their entireties for all purposes.

BACKGROUND

The present disclosure relates to apparatuses, systems, and methods forshoulder surgery, more particularly to rotator cuff sparing devices andmethods used during total shoulder arthroplasty.

Each year, many patients suffer from arthritis of the shoulder. Shoulderarthritis may arise from trauma, osteoarthritis, or secondary to otherarthritic processes such as rheumatoid arthritis. Shoulder arthroplastyhas become an advantageous surgery for patients that suffer fromshoulder pain. One of the drawbacks of the surgery is the need to takedown the rotator cuff so that the procedure may be performed. Shoulderarthroplasty has been performed traditionally from an anterior approachwhere the rotator cuff is removed and reattached at the end of the case.Shoulder replacement has traditionally shown good outcomes, but recoverymay take up to 6-12 months. One of the major complications of totalshoulder arthroplasty is rotator cuff failure and the pain andinstability associated with this issue. Additionally, a technical issuerelated to the surgery is the difficulty associated with exposure of theshoulder socket which, due to the arthritic process, may be directedposteriorly. Existing systems may be insufficient to address suchconcerns because of difficulties associated with effectively introducingand positioning implant components for shoulder arthroplasty.

SUMMARY

According to an aspect of the present disclosure, a humeral head implantsystem includes a head component, a base component, and an insertcomponent. The head component includes a first spherical articulatingsurface configured to articulate in a shoulder cavity, a second bottomsurface extending from a rim of the first spherical articulatingsurface, a first cavity extending a first distance into the headcomponent from the second bottom surface, and a second cavity extendinga second distance into the head component from the first cavity along acavity axis. The head component defines a head axis extending through acenter of the first spherical articulating surface, the head axis spacedfrom and parallel to the cavity axis. The base component defines a slotextending from a first slot width at a third surface of the basecomponent to a second slot width within the base component, the secondslot width greater than the first slot width. The insert componentincludes an insert body, a first engagement feature extending from theinsert body, and a slot engagement feature extending from an oppositeside of the insert body as the first engagement feature. The firstengagement feature is configured to be received in the second cavityalong the cavity axis to engage the insert component to the headcomponent. The insert body has an insert thickness less than the firstdistance of the first cavity, and the slot engagement feature isconfigured slide into the slot of the base component in a directiontransverse to the cavity axis while the insert component is engaged tothe head component.

According to another aspect of the present disclosure, a humeral headimplant system includes a head component, a base component, a firstinsert component, and a second insert component. The head componentincludes a first spherical articulating surface configured to articulatein a shoulder cavity, a second bottom surface extending from a rim ofthe first spherical articulating surface, a first cavity extending intothe head component from the second bottom surface, and a second cavityextending into the head component from the first cavity. The headcomponent defines a head axis extending through a center of the firstspherical articulating surface, the head axis spaced from and parallelto the cavity axis. The base component defines a slot extending into thebase component, the slot including a slot surface and a slot cavityextending further into the base component than the slot surface. Thefirst insert component is sized to be received within the second cavityof the head component, the first insert defining a third cavity havingan insert axis configured to be spaced from and parallel to the cavityaxis when the first insert component is received within the secondcavity. The second insert component includes a first region sized to bereceived in the third cavity of the first insert component and a secondregion sized to be received within the slot cavity of the basecomponent.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of an embodiment of a humeral head retractordevice.

FIG. 2 is a detail view of an embodiment of a grip feature of thehumeral head retractor device of FIG. 1.

FIG. 3 is a side view of an embodiment of the humeral head retractordevice of FIG. 1.

FIG. 4 is a detail view of an embodiment of a grip feature of thehumeral head retractor device of FIG. 1.

FIG. 5 is a detail view of an embodiment of a grip feature of thehumeral head retractor device of FIG. 1.

FIG. 6 is an isometric view of an embodiment of a humerus lift device.

FIG. 7 is a detail view of an embodiment of an attachment feature of thehumerus lift device of FIG. 6.

FIG. 8A is a side view of an embodiment of the attachment feature ofFIG. 7.

FIG. 8B is a front view of an embodiment of the attachment feature ofFIG. 7.

FIG. 9 is an isometric view of an embodiment of a glenoid retractordevice.

FIG. 10 is a detail view of an embodiment of an attachment feature ofthe glenoid retractor device of FIG. 9.

FIG. 11A is a side view of an embodiment of the glenoid retractor deviceof FIG. 9.

FIG. 11B is a front view of an embodiment of the glenoid retractordevice of FIG. 9.

FIG. 12 is an isometric view of an embodiment of a supraglenoid tubercleretractor device.

FIG. 13 is an isometric assembly view of an embodiment of humeral headinstruments.

FIG. 14 is a rotated isometric assembly view of an embodiment of thehumeral head instruments of FIG. 13.

FIG. 15 is an isometric assembly view of an embodiment of glenoidinstruments.

FIG. 16 is a rotated isometric assembly view of an embodiment of theglenoid instruments of FIG. 15.

FIG. 17A is a perspective view of an embodiment of a retractor device.

FIG. 17B is a top view of the retractor device of FIG. 17A.

FIG. 17C is a side view of the retractor device of FIG. 17A.

FIG. 18A is a perspective view of an embodiment of a humeral resectionguide.

FIG. 18B is a side view of the humeral resection guide of FIG. 18A.

FIG. 19A is a perspective view of an embodiment of a retractor device.

FIG. 19B is a detailed perspective view of a retractor portion of theretractor device of FIG. 19A.

FIG. 20A is a perspective view of an embodiment of a retractor device.

FIG. 20B is a side view of the retractor device of FIG. 20A.

FIG. 20C is a top view of the retractor device of FIG. 20A.

FIG. 21A is a perspective view of an embodiment of a retractor device.

FIG. 21B is a detailed perspective view of a tip portion of theretractor device of FIG. 21A.

FIG. 22A is a perspective view of an embodiment of an engagement device.

FIG. 22B is a top view of the engagement device of FIG. 22A.

FIG. 22C is a sectional view of the engagement device of FIG. 21A andFIG. 21B.

FIG. 23 is an exploded view of an embodiment of a humeral head implantsystem.

FIG. 24A is a perspective view of an embodiment of a head component of ahumeral head implant system.

FIG. 24B is a sectional view of the head component of FIG. 24A.

FIG. 24C is a bottom view of the head component of FIG. 24A.

FIG. 25A is a top perspective view of an embodiment of an insertcomponent of a humeral head implant system.

FIG. 25B is a side view of the insert component of FIG. 25A.

FIG. 25C is a bottom perspective view of the insert component of FIG.25A.

FIG. 25D is a top view of the insert component of FIG. 25A.

FIG. 25E is another side view of the insert component of FIG. 25A.

FIG. 25F is a bottom view of the insert component of FIG. 25A.

FIG. 26A is a top perspective view of an embodiment of a base componentof a humeral head implant system.

FIG. 26B is a side view of the base component of FIG. 26A.

FIG. 26C is a bottom perspective view of the base component of FIG. 26A.

FIG. 26D is a top view of the base component of FIG. 26A.

FIG. 26E is another side view of the base component of FIG. 26A.

FIG. 26F is a bottom view of the base component of FIG. 26A.

FIGS. 27A-27E illustrate various configurations of the humeral headimplant system of FIG. 23.

FIGS. 28A-28C illustrate various embodiments of engagement features ofan insert of a humeral head implant system.

FIG. 29 is an exploded view of another embodiment of a humeral headimplant system.

FIG. 30A is a perspective view of an embodiment of a head component of ahumeral head implant system.

FIG. 30B is a sectional view of the head component of FIG. 30A.

FIG. 30C is a bottom view of the head component of FIG. 30A.

FIG. 31A is a perspective view of an embodiment of an insert componentof a humeral head implant system.

FIG. 31B is a side view of the insert component of FIG. 31A.

FIG. 31C is a top view of the insert component of FIG. 31A.

FIG. 31D is a side view of the insert component of FIG. 31A.

FIG. 31E is a bottom view of the insert component of FIG. 31A.

FIG. 32A is a top view of an embodiment of a base component of a humeralhead implant system.

FIG. 32B is a top perspective view of the base component of FIG. 32A.

FIG. 32C is a first side view of the base component of FIG. 32A.

FIG. 32D is a second side view of the base component of FIG. 32A andFIG. 32E is a bottom view of the base component of FIG. 32A.

FIG. 32F is a bottom perspective view of the base component of FIG. 32A.

FIGS. 33A-33E illustrate various configurations of the humeral headimplant system of FIG. 29.

FIG. 34 is an exploded view of another embodiment of a humeral headimplant system.

FIG. 35A is a perspective view of an embodiment of a head component of ahumeral head implant system.

FIG. 35B is a sectional view of the head component of FIG. 35A.

FIG. 35C is a bottom view of the head component of FIG. 35A.

FIG. 36A is a perspective view of an insert component of a humeral headimplant system.

FIG. 36B is a side view of the insert component of FIG. 36A.

FIG. 36C is a bottom perspective view of the insert component of FIG.36A.

FIG. 36D is a top view of the insert component of FIG. 36A.

FIG. 36E is another side view of the insert component of FIG. 36A.

FIG. 36F is a bottom view of the insert component of FIG. 36A.

FIGS. 37A-37E illustrate various configurations of the humeral headimplant system of FIG. 34.

FIG. 38A is a schematic diagram illustrating an end view of an exampleshoulder anatomy.

FIG. 38B is a schematic diagram illustrating a side view of an exampleshoulder anatomy.

FIGS. 39A-39B are flow diagrams of an embodiment of a method ofperforming a posterior approach rotator cuff sparing total shoulderarthroplasty.

FIGS. 40A-40C are schematic diagrams illustrating example shoulderanatomies on which a posterior approach rotator cuff sparing totalshoulder arthroplasty is being performed.

FIGS. 41A-41Z are images illustrating an embodiment of performing theposterior approach rotator cuff sparing total shoulder arthroplasty ofFIGS. 39A-39B.

DETAILED DESCRIPTION

The following detailed description and the appended drawings describeand illustrate various shoulder arthroplasty retractor systems, methods,and components. The description and drawings are provided to enable oneof skill in the art to make and use one or more systems and/orcomponents, and/or practice one or more methods. They are not intendedto limit the scope of the claims in any manner.

The use of “e.g.” “etc.,” “for instance,” “in example,” and “or” andgrammatically related terms indicates non-exclusive alternatives withoutlimitation, unless otherwise noted. The use of “optionally” andgrammatically related terms means that the subsequently describedelement, event, feature, or circumstance may or may not bepresent/occur, and that the description includes instances where saidelement, event, feature, or circumstance occurs and instances where itdoes not. The use of “attached” and “coupled” and grammatically relatedterms refers to the fixed, releasable, or integrated association of twoor more elements and/or devices with or without one or more otherelements in between. Thus, the term “attached” or “coupled” andgrammatically related terms include releasably attaching or fixedlyattaching two or more elements and/or devices in the presence or absenceof one or more other elements in between. As used herein, the terms“proximal” and “distal” are used to describe opposing axial ends of theparticular elements or features being described in relation toanatomical placement.

In existing solutions, shoulder arthroplasty can result in long recoverytimes due to how the rotator cuff is removed in order to perform theprocedure. The present disclosure relates to devices, systems, andmethods for improving shoulder arthroplasty while preventing damage tothe rotator cuff, such as by using instruments that can position thehumerus and glenoid at an accessible orientation for implantinstallation without cutting the rotator cuff. The present disclosurealso relates to devices, systems, and methods for improving shoulderarthroplasty while preventing damage to the rotator cuff, such as byusing humeral head implant systems that can be manipulated and implantedmore easily and with less impact on the anatomy of the patient.

A. Rotator Cuff Sparing Devices and Methods

In some embodiments, retractor devices are used to position the humerusand glenoid at an accessible orientation for implant installation. Theretractor devices are also used to block anatomical structures fromimpeding the view of the humeral head and glenoid cup during implantpreparation and installation. The retractor devices have angled shaftand grip bodies that avoid anatomy and enable orientation to torquecreating lift, pull, and push forces on the anatomy. The retractordevices have teeth or other engagement structures to grip bone andmaximize contact area with retractor surfaces to provide improved torqueat the patient orientation angles. Additionally, the retractor deviceshave specific offset distances for matching humerus and glenoidstructures to allow torsion on hard bone surfaces for achieving implantpreparation view and access.

Referring now to FIGS. 1-3, a humeral head retractor device 100 isillustrated in accordance with one embodiment. The humeral headretractor can be configured to lift and retract the humeral head toexpose bone structures in and around the humeral head for shoulderarthroplasty procedures. The humeral head retractor device 100 includesa body 110 extending from a first body end 112 to a second body end 114,a handle 120 extending from the first body end 112, a plate 130extending from the second body end 114, and a retractor 140 extendingfrom an opposite end of the plate 130 from the second body end 114.

The body 110 can define a length from the first body end 112 to thesecond body end 114. The length can be approximately 8 inches. Thelength can be selected based on factors including control ofmanipulation of the retractor 140 (e.g., control over the retractor 140may increase as the length decreases) and/or a force required to beapplied by the retractor surface 140 to retract a humeral head (e.g.,the force that can be applied increases as a function of the length).

The handle 120 includes a first handle surface 122 and a second handlesurface 124 opposite the first handle surface 122. In some embodiments,the handle 120 includes a handle end 126. The handle end 126 is shown todefine an arc length of at least ninety degrees (e.g., relative to alongitudinal axis of the handle 120). The first handle surface 122,second handle surface 124 and/or the handle end 126 can providesurface(s) for receiving tools, or a hand of a user, for manipulatingthe humeral head retractor device 100. For example, the second handlesurface 124 can receive a force applied against the second handlesurface 124, and in response, the retractor surface 124 can betranslated in a direction corresponding to the force applied against thesecond handle surface 124. In some embodiments, an arc length definedfrom the first end 112 to a terminal end of the handle end 126 is atleast one-hundred twenty (120) degrees, such that a hand or manipulationdevice can be supported along the second handle surface 124 and used tomanipulate the humeral head retractor device 100.

The plate 130 connects the body 110 to the retractor surface 150. Asshown in FIG. 1, the plate 130 has a greater width than the body 110(e.g., the plate 130 extends past the body 110 on either side of thebody 110 in a direction transverse to a longitudinal axis of the body110). As such, the plate 130 can have a plate surface 132 that is widerthan the body 110, such that manipulation of the humeral head retractordevice 100 applies force via the plate surface 132 to move tissue in avicinity of the head of the humerus.

The retractor 140 is configured to engage and manipulate the head of thehumerus. The retractor 140 can include a retractor surface 142 thatextends from the plate 130. The retractor surface 142 can be shaped toengage the head of the humerus. For example, the retractor surface caninclude a first engagement surface 144 and a second engagement surface146. The first engagement surface 144 and second engagement surface 146extend away from (e.g., curve away from, provide an indent in theretractor surface 142, etc.) a plane defined by the retractor surface142, terminating in an outer engagement surface 148 as shown in FIG. 3.When manipulated, the retractor 140 can be slid underneath the humeralhead to engage (e.g., hook, attach to, secure, etc.) an opposite side ofthe head (e.g., opposite relative to a direction from which theretractor 140 is moved towards the humeral head), such as to pull thehumeral head into position. The first engagement surface 144 and secondengagement surface 146 can be configured to receive the humeral head(e.g., a volume of the humeral head fits into the space defined by thefirst engagement surface 144 and second engagement surface 146).

In some embodiments, the first engagement surface 144 and/or the secondengagement surface 146 define a dimension (for example, a diameter)corresponding to a corresponding dimension (for example, a diameter) ofthe head of the humerus. For example, the diameter defined by the firstengagement surface 144 can be within a threshold tolerance (e.g., 1%,5%, 10%, 20%) of the diameter of the head of the humerus. In someembodiments, a plane defined by the second engagement surface 146 isoriented at an angle relative to the first engagement surface 144 (e.g.,oriented at an obtuse angle), which may provide multiple engagementfeatures in a single device such that the humeral head retractor device100 can be used to manipulate heterogeneously shaped humeral heads.

The retractor 140 includes a retractor engagement feature 150. Theretractor engagement feature 150 is configured to engage the head of thehumerus. In some embodiments, the retractor engagement feature 150 isconfigured to engage (e.g., grip, hook, restrict motion of, apply forceagainst, etc.) the humeral head. For example, as the humeral head isreceived in the retractor surface 142, the retractor engagement feature150 can be positioned on a backside surface of the humeral head (e.g.,the retractor engagement feature 150 can engage the humeral head at agreater distance from the retractor surface 142 relative to a retractordevice that does not include engagement surfaces 144, 146 as shown inFIG. 2). In some embodiments, the plate surface 132 of the plate 130provides increased surface area to retract and protect the deltoidmuscle.

The retractor engagement feature 150 extends from the retractor 140 onan opposite side of the retractor from the plate 130. The retractorengagement feature 150 can include a first retractor portion 154 thatextends from the retractor surface 142. The first retractor portion candefine a width that is less than a width of the retractor surface 142(e.g., less than half a width of the retractor surface 142), which mayprovide greater precision in manipulating the retractor engagementfeature 150 relative to manipulation of other components of the humeralhead retractor device 100. The retractor engagement feature 150 caninclude a second retractor portion 158 that extends from the firstretractor portion 154. The second retractor portion 158 can be orientedat an angle relative to the first retractor portion 154 (e.g., an angleof approximately 90 degrees), such that together the first retractorportion 154 and the second retractor portion 148 define a curved (e.g.,hook-shaped) component for engaging the humeral head. The firstretractor portion 154 and second retractor portion 158 can define aninner engagement surface 162 which contacts and engages (e.g.,frictionally engages) the humeral head.

Referring now to FIG. 4, a retractor 170 of a humeral head retractordevice 100 is shown in accordance with one embodiment. The retractor 170can be similar to the retractor 140, with the exception of featuresrelating to the retractor engagement feature as described below.

The retractor 170 includes a retractor engagement feature 174. Theretractor engagement feature 174 includes a first retractor portion 178extending from a retractor surface 172 of the retractor 170 and a secondretractor portion 182 extending from the first retractor portion 178,the second retractor portion 182 being oriented at an angle relative tothe first retractor portion 178 (e.g., an angle of approximately ninetydegrees). Relative to the retractor engagement feature 150 of FIGS. 1-3,the first retractor portion 178 and second retractor portion 182 definea greater width (e.g., a width that is between 50% and 100% of a widthof the retractor surface 172). The relatively greater width may enable auser to more easily separate the humeral head from nearby tissue, suchas by increasing surface area of the retractor engagement feature 174(e.g., the greater surface area may facilitate retracting and protectinga deltoid muscle).

Referring now to FIG. 5, a retractor 190 of a humeral head retractordevice 100 is shown in accordance with one embodiment. The retractor 190can be similar to the retractors 140, 170, with the exception offeatures relating to the retractor engagement feature as describedbelow.

The retractor 190 includes a retractor engagement feature 194. Theretractor engagement feature 194 defines a width that is less than awidth of a retractor surface 192 of the retractor 190 (e.g., less thanone half of the width of the retractor surface 192). The retractorengagement feature 194 does not curve or hook as much as the retractorengagement feature 150 or the retractor engagement feature 174. Forexample, the retractor engagement feature 194 can have a curvature suchthat an angle defined by a point at which the retractor engagementfeature 194 intersects the retractor surface 192, a terminal end 196 ofthe retractor engagement feature 194, and another point along theretractor engagement feature 194 is greater than ninety degrees. Theterminal end 196 can be relatively blunt (e.g., have a greater depth ina direction transverse to the curvature direction) as compared to endsof the retractor engagement features 150, 174, so that for poor qualitybone, the retractor 190 does not hook into the bone and cause excessivecompression that could damage the surface of the bone during exposure.

Referring now to FIGS. 6-8, a humerus lift device 200 is shown inaccordance with one embodiment. The humerus lift device 200 isconfigured to lift and support the humerus, such as by following acontour of the humerus to slide underneath the humerus. In someembodiments, the humerus lift device 200 (or components thereof) definesa contoured profile matching a contour of the humerus, such that thehumerus lift device 200 may be inserted in a low-profile orientationoffset from the humerus. The humerus lift device 200 can be configuredto make contact with a transition from the humeral head to a shaftadjacent to the humeral head, which can assist with exposure and preventfracture when the humeral head is osteomized.

As shown in FIG. 6, the humerus lift device 200 includes a handle 210.The handle 210 can define a cylindrical shape with grip members 212 thatallow the handle 210 (and thus the humerus lift device 200) to be bothrotated and translated as the handle 210 is manipulated. The humeruslift device 200 includes a body 220 extending from a first end 222 to asecond end 224. The handle 210 extends from the second end 224 of thebody 220. The humerus lift device includes a lift member 230 thatextends from the first end 222 of the body 220. In some embodiments, thehandle 210 is configured to couple (e.g., mate, engage, attach to) auniversal hospital bed lift/traction system, to allow for pulling thehumerus at a desired height and angle for optimum orientation.

In some embodiments, the lift member 230 is configured to follow acontour of a bone (e.g., the humerus), such that manipulation of thehumerus lift device 200 allows for manipulation (e.g., lifting,supporting, etc.) of the humerus by the lift member 230. The lift member230 can include an extension 234 extending from the body 220 at thefirst end 222. The extension 234 can have a curved shape (e.g., theextension 234 can define a curvature less than or equal to ninetydegrees). The lift member 230 can include a first lift portion 238 thatextends from the extension 234 in a direction transverse to alongitudinal axis of the body 220. For example, the first lift portion238 can be positioned in a plane that is transverse to a longitudinalaxis of the body 220.

As shown in FIG. 8A, the first lift portion 238 can have a curvatureshaped to match a curvature of the humerus. For example, the first liftportion 238 can have a radius of curvature in a direction outwards fromthe extension 234 that is within a threshold or tolerance of a curvatureof the humerus (e.g., within 1%, within 5%, within 10%). As the humeruslift device 200 is manipulated to be slid along the humerus, the firstlift portion 238 can thus conform to the humerus, guiding the movementof the humerus lift device 200.

The lift member 230 can include a second lift portion 242. The secondlift portion 242 extends from a first end 240 of the first lift portion238. The second lift portion 242 can be tilted relative to the firstlift portion 238. For example, the second lift portion 242 (or alongitudinal axis thereof) can be located in a plane that is at an anglerelative to a plane (or a longitudinal axis thereof) that the first liftportion 238 is located in. As shown in FIGS. 7, 8A, and 8B, the anglecan be obtuse (e.g., greater than 90 degrees and less than 180 degrees;greater than 120 degrees and less than 180 degrees; greater than 150degrees and less than 180 degrees).

The angle at which the second lift portion 242 is oriented relative tothe first lift portion 238 can be selected such that the second liftportion 242 maintains a low profile, yet also makes contact at thetransition from the humerus to prevent fracture of the humerus. Forexample, the second lift portion 242 can be oriented at an anglerelative to the first lift portion 238 such that when the first liftportion 238 contacts the humerus, the second lift portion 242 ispositioned away from the humerus less than a threshold distance whilethe first lift portion 238 contacts and is slid along the humerus sothat the second lift portion 242 does not damage or interfere withtissue in the vicinity of the humerus. The threshold distance can bedefined as the shortest distance from a distal end of the second liftportion 242 to the humerus, and can be a function of a thickness of thefirst lift portion 238 (e.g., less than 10 times the thickness of thefirst lift portion 238, less than 5 times the thickness of the firstlift portion).

In some embodiments, such as shown in FIG. 8A, the second lift portion242 has a curvature. The curvature can be shaped to match a curvature ofthe humerus. The curvature of the second lift portion 242 may be similarto the curvature of the first lift portion.

Referring now to FIGS. 9-11, a glenoid retractor device 300 is shown inaccordance with one embodiment. The glenoid retractor device 300 can beconfigured to attach underneath a glenoid cavity with adequate offset toavoid interfering the glenoid when lifting for exposure.

The glenoid retractor device 300 include a body 310 that extends from afirst end 312 to a second end 314. The glenoid retractor device 300 caninclude a handle 320 that extends from the second end 314 of the body310. The handle 320 can be similar in structure and function to thehandle 120 of the humeral head retractor device 100, such as byproviding surfaces for forces applied against the handle 120 to causethe glenoid retractor device 300 to be manipulated.

The glenoid retractor device 300 can include a lift surface 330extending from the first end 312 of the body 310. The lift surface 330can be configured to engage a portion of a subject in or around aglenoid cavity. The lift surface 330 can include a first surface portion334 extending from the first end 312 of the body 310. The first surfaceportion 334 can be shaped to curve away from the body 310 (e.g., suchthat the first surface portion 334 is oriented in a plane transverse tothe body 310).

The lift surface 330 can include a second surface portion 338. Thesecond surface portion 338 can be shaped to curve away from the firstsurface portion 334 (e.g., such that the second surface portion 338 isoriented in a plane transverse to the first surface portion 334). Thesecond surface portion 338 can define an opening 336, allowing forvisibility through the second surface portion 338 and/or instruments tobe passed through the second surface portion 338.

The second surface portion 338 can define a first width at a first endadjacent to the first surface portion 334, and a second width oppositethe first end, such that the width of the second surface portion 338increases from the first end to the second end. In some embodiments, byincreasing the width of the second surface portion 338 from the firstend to the second end, components of the glenoid retractor device 300that extend from the first end (e.g., the first surface portion 334, thebody 310, the handle 320) can be shaped with a relatively lesser width,allowing for a low profile, while components extending from the secondend (e.g., an attachment feature 340 as described herein) can be shapedwith a relatively greater width, allowing for a greater surface area formanipulating bones in and around the glenoid.

The glenoid retractor device 300 can include an attachment feature 340.The attachment feature 340 can be configured to attach underneath aglenoid cavity. The attachment feature 340 can include an attachmentmember 342 that extends from the second surface portion 338. Theattachment member 342 can extend transverse to the second surfaceportion 338 (e.g., at an angle of approximately 90 degrees, such as anangle between 60 degrees and 90 degrees). This may allow a bone to bereceived on the second surface portion 338 and simultaneously supportedby the attachment member 342.

In some embodiments, the attachment member 342 terminates in one or moreengagement features 344. For example, as shown in FIG. 10, theattachment member 342 terminates in angled members 346 (e.g., ridges,teeth), that may engage a feature of a body of a subject in or aroundthe glenoid cavity to attach the glenoid retractor device 300. Theattachment member 342 can also terminate in an attachment receivingsurface 348. The attachment receiving surface 342 can be shaped to matcha shape of a bone structure of the patient in or around the glenoidcavity. For example, the attachment receiving surface 348 can define aradius of curvature that matches a radius of curvature of the bonestructure (e.g., the radius of curvature is within a threshold ortolerance of a curvature of the bone structure, such as being with 1%,within 5%, within 10%). The attachment receiving surface 348 canfacilitate manipulation of the glenoid retractor device 300, such as byaligning the glenoid retractor device 300 to the bone structure,allowing the angled members 346 to attach in the correct location.

Referring now to FIG. 12, a glenoid retractor device 400 is shown inaccordance with one embodiment. The glenoid retractor device 400 can besimilar to the glenoid retractor device 300, with the exception of theattachment features as described below.

As shown in FIG. 12, the glenoid retractor device 400 includes a body410 (but does not include a handle distinct from the body 410) extendingfrom a first end 412 to a second end 414. A first surface portion 418extends from the first end 412 of the body 410. The first surfaceportion 418 can be angled relative to the body 410 such that the firstsurface portion 418 curves away from the body 410.

An attachment feature 422 extends from the first surface portion 418.The attachment feature 422 can be angled relative to the first surfaceportion 418 such that the attachment feature 422 avoids the acromion andcoracoid process to increase access to bony structure underneath theglenoid cavity for additional glenoid exposure (see FIGS. 15, 16). Forexample, the attachment feature 422 can define an angle relative to thefirst surface portion of approximately 90 degrees (e.g., between 75 and105 degrees, between 85 and 95 degrees, between 90 and 100 degrees). Theattachment feature 422 includes a first attachment member 426 and asecond attachment member 430. The first attachment member 426 extends alesser distance than the second attachment member 430, such that theattachment feature 422 conforms to a shape of the glenoid when in use(e.g., see FIGS. 15, 16).

In various embodiments, devices such as the humeral head retractordevice 100, the humerus lift device 200, the glenoid retractor device300, and/or the glenoid retractor device 400 can include various anglesfor handles, and various grips (e.g., for coupling to a universaltraction system), to enable manipulation of the devices at variousangles depending on an anatomy of the patient, including features of apatient to avoid during an operation.

Referring now to FIGS. 13-14, an isometric assembly view of a humeralhead retractor device 100 and a humerus lift device 200 is shown inaccordance with one embodiment. The devices are being used to retract ahumeral head of a patient. Angles and orientations of approach for thedevices can be selected to minimize interference with an anatomy of thepatient, such as to avoid contacting bones other than the humerus or toavoid the rotator cuff.

Referring now to FIGS. 15-16, isometric assembly views of glenoidretractor devices 300, 400 are shown in accordance with one embodiment.The glenoid retractor devices 300, 400 can be attached anterior to aglenoid cavity. The shafts of the devices (e.g., second surface portion338 of glenoid retractor device 300) can be oriented at an angle ofapproximately 45 degrees relative to the head of the devices (e.g., anangle defined between the second surface portion 338 and the attachmentfeature 340 may be greater than or equal to 35 degrees and less than orequal to 55 degrees, greater than or equal to 40 degrees and less thanor equal to 50 degrees, greater than or equal to 44 degrees and lessthan or equal to 46 degrees, etc.). The handle 320 of the glenoidretractor device 300 may extend from the body 310 at an angle ofapproximately 120 degrees (e.g., greater than or equal to 90 degrees andless than or equal to 150 degrees, greater than or equal to 105 degreesand less than or equal to 135 degrees, greater than or equal to 110degrees and less than or equal to 130 degrees, etc.). This can allow thehandle 320 to be gripped by a user (e.g., a surgical assistant) suchthat hands of the user are clear of the surgical field (e.g., a line ofsight defined between the lift surface 330 and eyes of the user, asurgical camera, or along the body 310 is not blocked or otherwiseinterfered by the hands of the user). The glenoid retractor device 400has a double bend (e.g., bends at transitions from the body 410 to thefirst surface portion 418 and again from the first surface portion 418to the attachment feature 422), which can allow for retraction of theinferior lip and the superior aspect of the glenoid, to improve glenoidexposure.

Referring now to FIGS. 17A-17C, a retractor device 500 is illustrated inaccordance with one embodiment. The retractor device 500 can be similarto the humeral head retractor device 100 described herein, with theexception of the retractor and handle components as described furtherbelow.

As shown in FIGS. 17A-17C, the retractor device 500 includes a handleportion 510, a body portion 520, and a retractor portion 530. The handleportion 510 and the body portion 520 can define an angle α by which thehandle portion 510 and body portion 520 are oriented with respect to oneanother. The angle α can allow a direct line of sight along theretractor device 500 to the retractor portion 530 and the anatomy beingmanipulated by the retractor portion 530 (e.g., a hand of a user of theretractor device 500 placed on the handle portion 510 will not block,interrupt, or otherwise interfere with a line of sight from the user'seyes to the retractor portion 530 or along the body portion 520 to theretractor portion 530). The handle portion 510 can have a length thatcorresponds to an expected or average depth of a wound (e.g.,approximately 5 inches; greater than or equal to 2 inches and less thanor equal to 8 inches; greater than or equal to 4 inches and less than orequal to 6 inches; etc.). The retractor portion 530 can define acurvature that allows for retracting the head of the humerus. Theretractor portion 530 can define a span 532 from the body portion 520 toa terminal end of the retractor portion 530 of approximately 2.5 inches(e.g., greater than or equal to 1.5 inches and less than or equal to 3.5inches; greater than or equal to 2 inches and less than or equal to 3inches; etc.). The retractor portion 530 can define a radius 534 ofapproximately 2 to 3 inches (e.g., greater than or equal to 1 inch andless than or equal to 4 inches; greater than or equal to 2 inches andless than or equal to 3 inches; etc.).

Referring now to FIGS. 18A-18B, a humeral resection guide 900 (e.g., acutting jig) is illustrated in accordance with one embodiment. Thehumeral resection guide 900 can provide a flat cutting surface forresection, and unlike existing systems, includes a contact surface forcontacting the humeral head so that the humeral head resection guide canfit on a posterior aspect of the humeral head, such as for being bracedagainst the humeral head. The humeral resection guide 900 includes acurved contact surface 910 that can be positioned against the humeralhead. The humeral resection guide 900 includes a plurality of channels920 that can receive pins for pinning the humeral resection guide 900 inplace. The humeral resection guide 900 includes an engagement feature930 (e.g., a slot, a key slot) configured to receive an engagementdevice (e.g., engagement device 1000 described with reference to FIGS.22A-22B) for allowing a surgeon or other medical professional performinga shoulder arthroplasty procedure to keep their hands away from thearthroplasty site while manipulating the engagement device, such as theengagement device 1000. The engagement feature 930 can include a pair ofengagement walls 932 that extend from the contact surface 920 into aninterior of the humeral resection guide 900. A distance between theengagement walls 932 may increase towards the interior of the humeralresection guide 900.

Referring now to FIGS. 19A-19B, a retractor device 600 is illustrated inaccordance with one embodiment. The retractor device 600 can be similarto other retractor devices disclosed herein (e.g., glenoid retractordevice 300). The retractor device 600 can be configured to retractagainst the anterior glenoid to improve exposure. The retractor device600 includes a body 610 that extends from a first end 612 to a secondend 614. At the second end 614, the body 610 can define an opening(e.g., a cutout centered in the body 610) allowing for instrumentationto be placed through the opening. The body can have a width ofapproximately 3 cm (e.g., 3 cm, greater than 2 cm and less than 4 cm,greater than or equal to 2.5 cm and less than or equal to 3.5 cm). Theretractor device 600 can include a retractor section 616 extending fromthe first end 612 of the body 610. The retractor section 616 can definean opening (e.g., a cutout) 618. At a distal end of the retractorsection 616 (e.g., an end opposite the first end 612 of the body 610),an offset portion 620 can extend from the retractor section 616. Theoffset portion 620 can be oriented transverse to the retractor section616 (e.g., oriented at an angle of approximately 90 degrees). The offsetsection 620 can terminate in an arc-shaped toothed surface including anarc section 622 positioned between toothed sections 624. The offsetsection 620 can have a length of approximately 7 mm (e.g., 7 mm). Thelength can be defined from where the offset section 620 joins theretractor section 616 to where the offset section 620 terminates). Theoffset section 620 can be placed on a front portion of a socket of theshoulder as the socket is exposed. The arc section 622 can be sized tofit around a lower portion of the glenoid, allowing the toothed portions624 to be spaced by the arc section 622 and separately engage theglenoid on either side of the lower portion of the glenoid. In someembodiments, the offset section 620 does not include the arc section622, but instead may have teeth along an entire length of the offsetsection 620.

Referring now to FIGS. 20A-20C, a retractor device 700 is illustrated inaccordance with one embodiment. The retractor device 700 can be similarto other retractor devices disclosed herein (e.g., humeral headretractor device 100, etc.). The retractor device 700 can be configuredto retract the inferior humeral neck, so that the humeral neck and headcan be brought close to the rotator cuff split. The retractor device 700includes a body 710 extending from a first end 712 to a second end 714.The retractor device 700 includes a retractor section 720 extending fromthe first end 712. The retractor section 720 terminates in a retractorend 724 that defines a curved surface 726 (e.g., U-shaped).

In some embodiments, the retractor end 724 defines a beveled edge thathas a soft curve (e.g., having a radius of curvature that is no lessthan a threshold radius at any given point), which can allow for gentlebut strong retraction on the inferior humeral neck. In some embodiments,the retractor end 724 has a length of approximately 3 cm (e.g., 3 cm,greater than 2 cm and less than 4 cm, greater than or equal to 2.5 cmand less than or equal to 3.5 cm). The length of the retractor end 724can be configured to conform to the inferior humeral neck. In someembodiments, a first portion of the retractor section 720 adjacent tothe retractor end 724 curves at an angle of approximately 5 degrees awayfrom the retractor end 724, and a second portion of the retractorsection 720 curves at an angle greater than 5 degrees away from thefirst portion. The retractor end 724 can have a curved edge thatretracts a calcar of the humerus. The retractor device 700 can have acurved body, allowing for the surgical field to be clearly seen withoutobstruction (e.g., a user manipulating the retractor device 700 at thehandle of the retractor device 700 does not interrupt a line of sight tothe retractor end 724).

Referring now to FIGS. 21A-21B, a retractor device 800 is illustrated inaccordance with one embodiment. The retractor device 800 can be similarto other retractor devices disclosed herein (e.g., humeral headretractor device 100, etc.). The retractor device 800 can be configuredto fit into the bicipital groove to retract the humeral head for canalpreparation for a stemmed implant. The retractor device 800 includes atip portion 820 located at an end of the retractor device 800. The tipportion 820 can be approximately 4 cm (e.g., 4 cm, greater than 2 cm andless than 6 cm, greater than or equal to 3.5 cm and less than or equalto 4.5 cm). The tip portion 820 can terminate in a flat curved portion822 (e.g., a beveled portion) of approximately 2 cm in width, so thatthe tip portion 820 may fit inside a rotator interval and hold thehumeral head in place. As such, the tip portion 820 can fit inside thebicipital groove to evert the humerus. The retractor device 800 can beconfigured to curve away from the shoulder with a gentle curve (e.g., acurve having a radius of curvature less than a threshold radius), whichcan allow for adequate exposure on the superior humeral head. The tipportion 820 can taper to a terminal end so that the tip portion 820 canavoid large structures that would block the tip portion 820 relative toa tip portion having a more blunt face.

Referring now to FIGS. 22A-22C, an engagement device 1000 (e.g., aninsert) is illustrated in accordance with one embodiment. The engagementdevice 1000 can be configured to engage the engagement feature 930 ofthe humeral resection guide 900. The engagement device 1000 includes afirst portion 1010 that tapers to a second portion 1020. The secondportion 1020 can be inserted into the engagement feature 930. Forexample, the second portion 1020 can terminate in an end surface 1030that is inserted into or received first by the engagement feature 930.The end surface 1030 can have a similar or identical shape as to anopening defined by the engagement feature 930, such as for allowing atight fit between the engagement device 1000 and the engagement feature930. The engagement device 1000 can allow a surgeon or other medicalprofessional performing a shoulder arthroplasty procedure to keep theirhands away from the arthroplasty site while manipulating the engagementdevice 1000, improving line of sight to the arthroplasty site whilereducing invasiveness of the arthroplasty procedure. It should also beappreciated that there may not be sufficient space for a surgeon to usetheir hands to manipulate the humeral resection guide 900 whenperforming a surgery in this fashion, and as such, the use of theengagement device 1000 enables the surgeon to manipulate the humeralresection guide 900 despite the limited space.

The various apparatuses and systems herein can be used to performshoulder arthroplasty procedures in a manner that improves over existingprocedures by limiting rotator cuff trauma and improving shoulder socketexposure.

In some embodiments of a shoulder arthroplasty procedure, the posteriorskin of the shoulder is incised overlying the posterior shoulder jointin line with the deltoid fibers. A retractor device may be used tosafely and easily retract and protect the deltoid. For example, theretractor device may have long arms and curved, cupped edges to protectthe deltoid. The lower border of the deltoid is identified and dissectedfree. The deltoid is split in line with its fibers over the apex of thehumeral head. The midportion of the humeral head is identified. Therotator cuff is split between the infraspinatus and the teres minor. Twomuscular windows are established superior and inferior to the deltoidsplit. Subsequently, the rotator cuff muscle is dissected down itslength both in the deltoid window and the window below it.

The rotator cuff is elevated to slacken it and the muscle is elevatedfrom the underlying capsular tissue. The capsule is released along thelabrum and released along the neck of the humerus. The humeral head isthen osteotomized. Modified crego retractor devices (e.g., retractordevice 500) are placed posterior to the humeral head. The retractordevice 500 includes angled arms (e.g., handle 510) that can allow forthe humeral head to be directly visualized, creating an assessment ofhumeral version. Subsequently, a humeral resection guide (e.g., humeralresection guide 900) is placed along the version provided by theretractor devices. The humeral resection guide 900 is then pinned intoplace. The humeral head is then osteotomized using the humeral headresection guide.

The anterior labrum and capsule are exposed and released. Now therelease is taken down the neck of the humerus and scapula to free up thesubscapularis. The shoulder is adducted and forward flexed and humeralhead retractor devices (e.g., humeral head retractor device 100) areapplied to assist in the exposure of the humeral head osteotomy site.The humeral head exposure can be assisted by a curved retractor thatfits along an inferior calcar (e.g., retractor device 700). A retractordevice to retract the biceps groove (e.g., retractor device 800) can beplaced into the bicipital groove to assist with retraction around thehumeral head. The retractor devices described herein can assist withdelivering the shoulder to a surgeon so that broaching and reaming canbe performed. In some embodiments, a retractor device that provides asling for the humeral shaft and provides posterior retraction canimprove exposure (e.g., humerus lift device 200).

The glenoid may be reamed as necessary. For example, the glenoid may bereamed utilizing an anterior glenoid retractor device (e.g., retractordevice 600) that allows for exposure of the glenoid. The teeth of theretractor device 600 and the offset between the teeth can allow forimproved glenoid exposure by fitting to the end of the glenoid. A 90degree reamer and drill are utilized to improve the ability to ream andplace glenoid components. Trial implants are placed. Closure isperformed. Alternatively, a standard anterior approach is performed tothe humeral head.

B. Humeral Head Implant System

Referring now to FIGS. 23-27C, a humeral head implant system 1100 isshown according to an embodiment. In some embodiments, the humeral headimplant system 1100 is configured to be used during total shoulderarthroplasty procedures. For example, the humeral head implant system1100 may be used to avoid damage to the rotator cuff by facilitating aposterior approach. For example, in such an approach, a split of themiddle and posterior heads of the deltoid and internervous plane betweenthe teres minor and infraspinatus may be used, improving on existingprocedures by avoiding subscapularis dysfunction or rupture, improvingaccess to the retroverted glenoid, and enabling posterior soft tissuebalancing to be performed. In addition, visualization of the humerus andglenoid may be improved over rotator interval andsubscapularis-splitting approaches, such as when inserting a basecomponent (e.g., a baseplate) of the humeral head implant system 1100,or when attaching a head component to the base component.

The humeral head implant system 1100 includes a head component 1120, aninsert component 1140, and a base component 1160. The head component1120 is configured to engage, attach, or otherwise be coupled to theinsert component 1140, such as by a Morse taper engagement. The insertcomponent 1140 includes an engagement surface configured to slide into acorresponding slot of the base component 1160. In some embodiments, thehumeral head implant system 1100 improves over existing solutions byallowing a surgeon or other operator installing or implanting the system1100 to secure the base component 1160 at an implant site, then slidethe insert component 1140 and head component 1120 (e.g., when the insertcomponent 1140 and head component 1120 have been coupled or engaged)into the slot, providing a more accessible manner of implanting the headcomponent 1120. For example, as compared to existing systems, in someembodiments the humeral head implant system 1100 can enable precise andvaried arrangements of the head component 1120, insert component 1140,and base component 1160, even in restrictive conditions where theanatomy of the patient may limit the spacing available for installingthe humeral head implant system 1100.

Referring further to FIGS. 24A-24C, an embodiment of the head component1120 is illustrated. The head component 1120 includes a surface 1122(e.g., an articulating surface) and an outer rim 1124. The surface 1112can have a domed, spherical, ellipsoidal, or otherwise rounded shape,allowing for a remote component to articulate along the surface 1122. Asdescribed further herein, dimensions of the head component 1120,including height h1 and diameter d1, can define a shape of the surface1122. The height h1 and/or diameter d1 can be selected to facilitatematching the surface 1122 to an anatomical feature selected toarticulate about the surface 1122 and/or to fit the head component 1120to an implant site. A ratio of the height h1 to the diameter d1 can bevaried based on an expected geometry of the implant site. In someembodiments, increasing the height h1 relative to the diameter d1 mayincrease a range of motion enabled by the head component 1120, but mayalso increase a profile or form factor of the head component 1120 (e.g.,make the head component 1120 less of a low profile device).

The head component 1120 can include a first cavity 1126 (e.g., hole,opening) configured to receive an engagement feature of the insertcomponent 1140, such as by a Morse taper engagement. The first cavity1126 can taper (e.g., decrease in radius) from a first end at which theengagement feature of the insert component 1140 can be received to asecond end. The first cavity 1126 can have a first diameter at the firstend which is within a threshold of a maximum diameter of an engagementfeature 1142 of the insert component 1140. The first cavity 1126 canhave a height h2 which is within a threshold of a height h5 of theengagement feature 1142.

The head component 1120 can also include a second cavity 1127 defined bya receiving wall 1128, which can allow a body of the insert component1140 to be received inside the head component 1120, such as to allow thehead component 1120 to sit flush against the base component 1160. Forexample, a height h3 of the receiving wall 1128 can be equal to orwithin a tolerance threshold of a height h5 of an insert body 1144 ofthe insert component 1140, such that when the insert body 1144 isreceived in the second cavity 1127, a substantial or entire volume ofthe insert body 1144 fits within the second cavity 1127. As such, thehead component 1120 can be coupled to the base component 1160 via theinsert component 1140 without increasing an effective profile of thehumeral head implant system 1100 due to a volume of the insert component1140.

The head component 1120 can define a head axis 1129. The head axis 1129can be a central axis of the head component 1120. For example, a pointalong the head axis 1129 on the surface 1122 can be equidistant frommany, most, or all points of the outer rim 1124. A point along the headaxis 1129 in a plane including the outer rim 1124 can also beequidistant from many, most, or all points of the outer rim 1124. Thehead axis 1129 can be perpendicular to the plane including the outer rim1124. The head axis 1129 can pass through a center of the head component1120, the center defined as a point equidistant from many, most, or allpoints on the surface 1122. The head axis 1129 can pass through a centerof the head component 1120 (e.g., a center of a spherical volume definedby the articulating surface 1122).

The cavity 1126 can define a cavity axis 1130. The cavity axis 1130 canbe a central axis of the cavity 1126. The cavity axis 1130 can beequidistant from many, most, or all points along the surface of thecavity 1126. The cavity axis 1130 can be parallel to the head axis 1129.The cavity axis 1130 can be perpendicular to the plane containing theouter rim 1124.

In some embodiments, the head component 1120 is configured to beeccentric. As shown in FIG. 24B, the cavity axis 1130 can be offset fromthe head axis 1129 by an offset 1131. As the head component 1120 isrotated about the insert component 1140, a greater or lesser volume ofthe head component 1120 can sit above the base component 1160. Forexample, the offset 1131 may define a greater volume of the headcomponent 1120 on a first portion of the head component 1120 throughwhich the head axis 1129 passes, and a lesser volume of the headcomponent 1120 on a second portion of the head component 1120 throughwhich the head axis 1129 does not pass. As the head component 1120 isrotated about the insert component 1140 (e.g., while coupled to theinsert component 1140 when the engagement feature 1142 is received inthe cavity 1126), a location of the greater volume may change relativeto the insert component 1140 (and similarly, a location of the lesservolume). As will be described further herein with reference to the basecomponent 1160, the eccentricity of the head component 1120 (e.g.,configuring the head component 1120 to include the offset 1131) canallow an offset between an axis of the base component 1160 and the headaxis 1129 of the head component 1120 to be varied. In some embodiments,the humeral head implant system 1100 is configured such that an axialoffset between the head component 1120 and the base component 1160 canbe varied.

The head component 1120 can be sized to fit into an implant sitetargeted for total shoulder arthroplasty. The head component 1120 canhave a height h1 of approximately 21 mm (e.g., 21 mm; greater than orequal to 10 mm and less than or equal to 30 mm). The cavity 1126 canhave a height h2 of approximately 10.5 mm (e.g., 10.5 mm; greater thanor equal to 5 mm and less than or equal to 21 mm). The receiving wall1128 can have a height of approximately 2 mm (e.g., 2 mm; greater thanor equal to 1 mm and less than or equal to 4 mm). The cavity 1126 (e.g.,a rim of the cavity 1126 defining an opening into the cavity 1126) canhave a radius r1 of approximately 10.05 mm (e.g., 10.05 mm; greater thanor equal to 5 mm and less than or equal to 20 mm). The head component120 can have a diameter d1 (e.g., a diameter defined by the outer rim1124) of approximately 49.11 mm (e.g., 49.11 mm; greater than or equalto 24 mm and less than or equal to 100 mm).

Referring further to FIGS. 25A-25F, an embodiment of the insertcomponent 1140 is illustrated. The insert component 1140 includes anengagement feature 1142, an insert body 1144, and a slot engagementfeature 1146. In some embodiments, the insert component 1140 may beintegrally formed with the head component 120. In some embodiments, theinsert component 1140 may be removably coupled to the head component120. In some embodiments, insert component 1140 may be permanentlycoupled with the head component 120. In some embodiments, the insertcomponent 1140 may slidably coupled with the head component 120.

The engagement feature 1142 is configured to engage the cavity 1126(e.g., by a Morse taper engagement). The engagement feature 1142 can besized to fit within the cavity 1126. For example, a diameter d2 of theengagement feature 1142 can be less than or equal to a maximum diameterof the cavity 1126. The diameter d2 may also be greater than or equal toa minimum diameter of the cavity 1126. The engagement feature 1142 canhave a surface curvature matching a surface curvature of the engagementfeature 1142. In some embodiments, the engagement feature 1142 isconfigured to be selectively rotated within the cavity 1126. Forexample, the engagement feature 1142 can be shaped, sized, and/orinclude surface engagement features to enable rotation of the engagementfeature 1142 relative to the cavity 1126 to adjust a relativeorientation of the head component 1120 and the insert component 1140,yet restrict rotation of the head component 1120 relative to the insertcomponent 1140 when the humeral head implant system 1100 is implanted.Alternatively, the engagement feature 1142 can be shaped, sized, and/orinclude surface engagement features to restrict rotation of the headcomponent 1120 relative to the insert component 1140 unless the headcomponent 1120 and insert component 1140 are not coupled. The engagementfeature 1142 and/or cavity 1126 can include relatively high frictionsurfaces configured to restrict rotation of the insert component 1140relative to the cavity 1126 unless a rotational force applied to theinsert component 1140 or head component 1120 is greater than a thresholdforce. The threshold force may be greater than an expected force duringimplantation or operation of the humeral head implant system 1100.

The slot engagement feature 1146 is configured to engage a slot of thebase component 1160 (e.g., slide into the slot). The insert component1140 can advantageously allow a user to slide the insert component 1140and head component 1120 together into the base component 1160 using lessphysical space in and around the implant site than existing systems. Theslot engagement feature 1146 can provide tactile feedback as the insertcomponent 1140 is slid into the base component 1160, even if the insertcomponent 1140 is coupled to the head component 1120 such that the slotengagement feature 1146 may be partially or completely obscured from aline of sight of a user by the head component 1120.

In some embodiments, the slot engagement feature 1146 has a dovetailshape to facilitate a secure engagement to the base component 1160. Forexample, a first end of the slot engagement feature 1146 at which theslot engagement feature 1146 extends from the insert body 1144 can havea first width that is less than a second with at a second end of theslot engagement feature 1146 opposite the first end. In someembodiments, the slot engagement feature 1146 restricts a separationfrom the base component 1160 responsive to a force applied to the slotengagement feature 1146 in a direction other than along a longitudinalaxis of the slot engagement feature 1146 (by which the slot engagementfeature 1146 may be received by the base component 1160). It should beappreciated that other slot engagement feature may have another shape ordesign to facilitate a slidable engagement to the base component.

The insert component 1140 can define an insert axis 1149. The insertaxis 1149 can pass through a center of the insert component 1140 and/orthe insert body 1142, such as a centroid or center of mass. The insertaxis 1149 can be perpendicular to a surface 1152 of the insert body1142. The insert axis 1149 can be equidistant from many, most, or allpoints on a rim surface 1153 of the insert body 1142.

The engagement feature 1142 can define an engagement axis 1150. Theengagement axis 1150 can pass through the engagement feature 1142. Theengagement axis 1150 can be equidistant from many, most, or all pointson a surface of the engagement feature 1142. The engagement axis 1150can be parallel to the insert axis 1149. The engagement axis 1150 can beperpendicular to a plane including the surface 1152.

In some embodiments, an orientation of the head component 1120 relativeto the insert component 1140 and/or the base component 1160 can bealtered based on rotation of the head component 1120 about theengagement axis 1150. When the engagement feature 1142 is received inthe cavity 1126, the engagement axis 1150 may align with the cavity axis1130 of the cavity 1126. In a first configuration, the insert axis 1149may align with the head axis 1129 when the engagement feature 1142 isreceived in the cavity 1126. In a second configuration or a plurality ofsecond configurations, the insert axis 1149 may be offset from the headaxis 1129 when the engagement feature 1142 is received in the cavity1126. The insert axis 1149 may be parallel to the head axis 1129 whileoffset. The humeral head implant system 1100 may be adjusted between thefirst configuration and one or more of the plurality of secondconfigurations based on rotation of the head component 1120 relative tothe engagement feature 1142 about the engagement axis 1150.

A magnitude of the offset may be varied based on rotation of the headcomponent 1120 about the engagement axis 1150. For example, themagnitude of the offset may increase from a first, minimum value (e.g.,the offset may be zero when the insert axis 1149 is aligned with thehead axis 1129 at the first configuration) to a second, maximum value(e.g., the offset may be greatest when the head component 1120 has beenrotated 180 degrees about the engagement axis 1150 from the firstconfiguration), and may decrease from the second, maximum value to thefirst, minimum value (e.g., when the head component 1120 is rotated 180degrees further to complete a 360 degree rotation about the engagementaxis 1150). When the insert component 1140 is coupled to the basecomponent 1160, the rotation of the head component 1120 about theengagement axis 1150 may also cause a change in orientation of the headcomponent 1120 relative to the base component 1160. In some embodiments,enabling the head component 1120 to be changed in orientation relativeto the base component 1160 enables anatomic restoration of the humeralhead of the patient. Similarly, when implanting the humeral head implantsystem 1100, there may be a limited selection of locations at which thebase component 1160 may be implanted, such that changing the orientationof the head component 1120 allows for anatomic restoration in ways thatwould not otherwise be possible.

The insert component 1140 can be sized and shaped to couple the headcomponent 1120 to the base component 1160. The engagement feature 1142can have a shape, including a diameter d2 of approximately 10.05 mm(e.g., 10.05 mm; greater than or equal to 5 mm and less than or equal to20 mm) to match the diameter d1 and shape of the cavity 126. The insertbody 1144 can have a diameter d3 of approximately 38.08 mm (e.g., 38.08mm; greater than or equal to 20 mm and less than or equal to 80 mm). Theinsert component 1140 can have a height h4 of approximately 14 mm (e.g.,14 mm; greater than or equal to 7 mm and less than or equal to 28 mm).The engagement feature 1142 can have a height h5 of approximately 9.50mm (e.g., 9.50 mm; greater than or equal to 4 mm and less than or equalto 20 mm). The slot engagement feature 1146 can have a height h6 ofapproximately 2.5 mm (e.g., 2.5 mm; greater than or equal to 1 mm andless than or equal to 5 mm). The slot engagement feature 1146 can have afirst width w1 (e.g., a width adjacent to the insert body 1144) ofapproximately 13.11 mm (e.g., 13.11 mm; greater than or equal to 6 mmand less than or equal to 27 mm) and a second width (e.g., a width at anopposite end of the insert body 1144 from the first width w1) ofapproximately 16 mm (e.g., 16 mm; greater than or equal to 8 mm and lessthan or equal to 32 mm).

Referring further to FIGS. 4A-4F, an embodiment of the base component1160 is illustrated. The base component 1160 includes a first surface1162 and a slot 1164. The first surface 1162 is configured to bepositioned adjacent to the insert component 1140 and/or inserted intothe cavity defined by the receiving wall 1128.

The slot 1164 may be defined within the first surface 1162 or may extendinto a body of the base component 1160 from the first surface 1162. Theslot 1164 may be configured, sized, and/or shaped to receive the slotengagement feature 1146 of the insert component 1140. In someembodiments, the slot 1164 includes a dovetail receiving featureconfigured to receive a dovetail feature of the slot engagement feature1146. The dovetail receiving feature may enable a secure fit between thebase component 1160 and the insert component 1140, such that a forceapplied to the base component 1160 or the insert component 1140 may notcause the base component 1160 to separate from the insert component 1140unless a component of the force is parallel to a longitudinal axis ofthe slot 1164 (e.g., unless the insert component 1140 is slid out of theslot 1164). A first width of the slot 1164 where the slot extends fromthe first surface 1162 and a second width of the slot 1164, which isgreater than the first width, may each be selected or configured tomatch corresponding widths of the slot engagement feature 1146, whichcan restrict movement of the insert component 1140 relative to the basecomponent 1160 while the insert component 1140 is engaged with the basecomponent 1160 unless the insert component 1140 is translated along alongitudinal axis of the slot 1164 (e.g., unless the insert component1140 is slid along the slot 1164).

In some embodiments, the base component 1160 includes an extension 1166,a first leg 1168 (e.g., a leg or stem having a relatively lesser length;a leg extending a radial distance from the extension 1166 less than aradius of the first surface 1162), and a pair of second legs 1170 (e.g.,legs or stems having a relatively greater length; legs extendingradially from the extension 1166 by a radial distance equal to theradius of the first surface 1162). The second legs 1170 can extend thesame distance from the extension 1166. Having a relatively shorter firstleg 1168, which can be positioned superiorly, can facilitate insertionof the base component 1160 at the implant site; having relatively longerlegs 1170, which can be positioned inferiorly, can allow rotationalcontrol and stability, as opposed to a configuration with all equallysized legs which may be difficult to use in a posterior approach. Insome embodiments, the base component 1160 is configured such that atleast one of the first leg 1168 or second legs 1170 extends at 90degrees or approximately ninety degrees (e.g., greater than or equal to75 degrees and less than or equal to 105 degrees; greater than or equalto 85 degrees and less than or equal to 95 degrees) relative to anotherof the first leg 1168 or second legs 1170, which may increase stabilityof the base component 1160.

The base component 1160 can be sized, shaped, and/or configured toengage or otherwise be coupled to the insert component 1140 and the headcomponent 1120. The base component 1160 can have a radius r3 ofapproximately 19.04 mm (e.g., 19.04 mm; greater than or equal to 9 mmand less than or equal to 40 mm). The slot 1164 can have a width w3 ofapproximately 13.11 mm (e.g., 13.11 mm; greater than or equal to 6 mmand less than or equal to 27 mm). The extension 1166 can have a diameterd4 of approximately 11 mm (e.g., 11 mm; greater than or equal to 5 mmand less than or equal to 22 mm) and a diameter d5 of approximately14.79 mm (e.g., 14.79 mm; greater than or equal to 7 mm and less than orequal to 30 mm). The leg 1168 can have a radius r4 of approximately 12.5mm (e.g., 12.5 mm; greater than or equal to 6 mm and less than or equalto 25 mm).

Referring further to FIGS. 27A-27E, various views of the humeral headimplant system 1100 are shown according to various configurations,orientations, and embodiments.

Referring further to FIGS. 28A-28C, various embodiments of theengagement feature 1142 of the insert component 1140 are illustrated.For example, the engagement feature 1142 can be located, positioned, orotherwise included in the insert component 1140 at various radialdistances from a center of the insert component 1140, such as to allowfor various ranges of motion, orientation, or eccentricity of the headcomponent 1120 relative to the insert component 1140. As shown in FIG.28A, the insert axis 1149 and engagement axis 1150 may be aligned, suchthat there is no offset between the insert axis 1149 and engagement axis1150. As shown in FIGS. 28B-28C, a magnitude of the offset 1151 may bevaried as the position of the engagement feature 1142 is varied.

Referring now to FIGS. 29-33E, a humeral head implant system 1200 isshown according to an embodiment. The humeral head implant system 1200can be similar to the humeral head implant system 1100, and can includefurther features relating to the engagement between the insertcomponents 1240, 1250 and the head component 1220, and between theinsert component 1250 and the base component 1260, as described furtherherein. The system 1200 can include a head component 1220, a firstinsert component 1240, a second insert component 1250, and a basecomponent 1260. The first insert component 1240 is configured to engageor otherwise couple to the head component 1220, such as by a Morse taperengagement. The second insert component 1250 is configured to engage orotherwise couple to the first insert component 1240 and to the basecomponent 1260, such as by a Morse taper engagement

The first insert component 1240 can include or define a first insertcavity 1242 configured to receive the second insert component 1250. Thefirst insert cavity 1242 can be sized, shaped, and/or configured tomatch a shape of the second insert component 1250.

Referring further to FIGS. 8A-8C, the head component 1220 (and/or thefirst insert component 1240 when received in the head component 1220)includes an articulating surface 1222, an outer rim 1224, a cavity 1226,and a receiving wall 1228. The head component 1220 can be sized, shaped,or otherwise configured for dual eccentricity (e.g., allowing for tworadial degrees of motion for selecting a relative orientation of thehead component 1220 to the base component 1260) and for engaging thefirst insert component 1240 and/or the second insert component 1250.Similar to the relationship between the cavity 1126 and the engagementfeature 1142, the cavity 1226 can be shaped to match a shape of theinsert component 1240, such that the first insert component 1240 can besecurely received in the cavity 1226. As shown in FIG. 30C, a center ofthe cavity 1226 (or a cavity axis of the cavity 1226) may be offset froma center of the head component 1220 (or the head axis 1229) by an offsetdistance d7.

The head component 1220 can define a head axis 1229. The head axis 1229can be defined in a similar manner to the head axis 1129 of the headcomponent 1120. For example, the head axis 1229 can be perpendicular toa plane including the outer rim 1224 and equidistant from many, most, orall points of the outer rim 1224. The head axis 1229 can pass through acenter of the surface 1222.

The head component 1220 can have a radius r5 of approximately 25 mm(e.g., 25 mm; greater than or equal to 12 mm and less than or equal to50 mm). The head component 1220 can have a height h6 of approximately 21mm (e.g., 21 mm; greater than or equal to 10 mm and less than or equalto 42 mm). The head component 1220 can have a height h7 of approximately2 mm (e.g., 2 mm; greater than or equal to 1 mm and less than or equalto 4 mm). The head component 1220 can have a diameter d6 ofapproximately 35 mm (e.g., 35 mm; greater than or equal to 17 mm andless than or equal to 70 mm). The offset distance d7 may beapproximately 3 mm (e.g., 3 mm; greater than or equal to 1 mm and lessthan or equal to 6 mm). The head component 1220 can have a radius r6 ofapproximately 21.80 mm (e.g., 21.80 mm; greater than or equal to 10 mmand less than or equal to 42 mm). The head component 1220 can have aradius r7 of approximately 9.5 mm (e.g., 9.5 mm; greater than or equalto 4 mm and less than or equal to 19 mm).

Referring further to FIGS. 31A-31E, the second insert component 1250includes a first region 1252 and a second region 1254. The first region1252 can be sized, shaped, and/or configured to be received in and/orengage the first insert component 1240 (e.g., a cavity thereof). Thesecond region 1254 can be sized, shaped, and/or configured to bereceived in and/or engage the base component 1260 (e.g., a slot orcavity thereof). The second region 1254 includes a first surface 1256configured, sized, and/or shaped to slide along the slot of the basecomponent 1260. The second region 1254 includes a second surface 1258configured to fit or engage (e.g., by a Morse taper) a cavity of theslot of the base component.

The second insert component 1250 can have a radius r8 of approximately4.75 mm (e.g., 4.75 mm; greater than or equal to 2 mm and less than orequal to 10 mm). The second insert component 1250 can have a height h8of approximately 17 mm (e.g., 17 mm; greater than or equal to 8 mm andless than or equal to 34 mm). The second insert component 1250 can havea height h9 of approximately 8 mm (e.g., 8 mm; greater than or equal to4 mm and less than or equal to 16 mm). The first surface 1256 of thesecond region 1254 can have a width w6 of approximately 7 mm (e.g., 7mm; greater than or equal to 3.5 mm and less than or equal to 14 mm).

Referring further to FIGS. 32A-32F, the base component 1260 can includebase surface 1262, a slot 1264, and a slot cavity 1265 configured toreceive the second insert component 1250. The base component 1260 canalso include an extension 1266, a first leg 1268, and a pair of secondlegs 1270.

The slot 1264 can have a ramp feature, a base surface, and/or side wallssized, shaped, or otherwise configured to receive and engage the secondinsert component 1250. For example, the second insert component 1250 canbe aligned with the edges of the slot 1264 such that the walls of thefirst surface 1256 fit against the side walls of the slot 1264, suchthat a user can slide the second insert component 1250 (e.g., with thefirst insert component 1240 and the head component 1220 coupled to thesecond insert component 1250) along the slot 1264 into the slot cavity1265.

The base component 1260 can have a height h10 of approximately 27.98 mm(e.g., 27.98 mm; greater than or equal to 13 mm and less than or equalto 56 mm). The base component 1260 can have a height h11 ofapproximately 2 mm (e.g., 2 mm; greater than or equal to 1 mm and lessthan or equal to 4 mm). The base component 1260 can have a radius r9 ofapproximately 17.50 mm (e.g., 17.50 mm; greater than or equal to 8 mmand less than or equal to 35 mm). The base component 1260 can have aheight r10 of approximately 11.50 mm (e.g., 5 mm; greater than or equalto 11.50 mm and less than or equal to 23 mm). The base component 1260can have a width w7 of approximately 7 mm (e.g., 7 mm; greater than orequal to 3.5 mm and less than or equal to 14 mm). The base component1260 can have a diameter d11 of approximately 11 mm (e.g., 11 mm;greater than or equal to 5 mm and less than or equal to 22 mm). The basecomponent 1260 can have a diameter d12 of approximately 14.79 mm (e.g.,14.79 mm; greater than or equal to 7 mm and less than or equal to 29mm). The base component 1260 can define a base axis 1272. The base axis1272 can be perpendicular to the slot 1264. The base axis 1272 can passthrough or include a center of the base component 1260. The base axis1272 can be equidistant from many, most, or all points of the basesurface 1262 or a rim of the base surface 1262, and can be perpendicularto a plane including the base surface 1262 or a rim of the base surface1262.

In some embodiments, the humeral head implant system 1200 is configuredsuch that the head axis 1229 can be offset from the base axis 1272 basedon rotation or orientation of the head axis 1229 about an engagementaxis of at least one of the first insert component 1240 or the secondinsert component 1250. For example, a configuration of the headcomponent 1220 relative to the base component 1260 can be varied basedon a rotation or orientation of at least one of (1) the head component1220 relative to the first insert component 1240; (2) the first insertcomponent 1240 relative to the second insert component 1250; or (3) thesecond insert component 1250 relative to the base component 1260. Insome such embodiments, the humeral head implant system 1200 may enablemore precise configuration of the head component 1220 relative to thebase component 1260 while maintaining a low profile form factor for thehumeral head implant system 1200 during and subsequent to implantation.For example, the first insert component 1240 and second insert component1240 enable at least two degrees of rotational freedom for adjusting howthe volume of the head component 1220 can be positioned relative to thebase component 1260.

Referring further to FIGS. 33A-33E, various views of the humeral headimplant system 1200 are shown according to various configurations,orientations, and embodiments. In some embodiments, such as shown inFIG. 33E, surfaces of the head component 1220 (e.g., surfaces from whichthe cavity 1226 extends) can be shaped to allow for accurate humeralhead sizing when restoring a natural anatomy of a patient and a geometryof the humeral head.

Referring now to FIGS. 34-37E, a humeral head implant system 1300 isshown according to an embodiment. The humeral head implant system 1300can be similar to the systems 1100, 1200 described herein. For example,the humeral head implant system 1300 includes the base component 1160 ofthe system 1100. The humeral head implant system 1300 includes a headcomponent 1320, a first insert component 1340, and a second insertcomponent 1350. The second insert component 1350 may be received withina cavity of a head component 1320 of the humeral head implant system1300 independent of an orientation of the head component 1320 relativeto the base component 1160, which can allow for a more secureimplantation of the humeral head implant system 1300. For example, thesecond insert component 1350 can be received such that the headcomponent 1320 sits flush against the base component 1160 in dependentof an orientation of the head component 1320, such as an angularposition of the head component 1320. The first insert component 1340includes a first insert cavity 1342 configured to receive the secondinsert component 1350.

Referring further to FIGS. 35A-35C, the head component 1320 includes asurface 1322 and an outer rim 1324. The head component 1320 includes ordefines a first cavity 1326. The first cavity 1326 is configured toreceive the first insert component 1340. The head component 1320includes or defines a second cavity 1327. The second cavity 1327 can bedefined by a receiving wall 1328.

As shown in FIG. 35C, the head component 1320 is configured to beeccentric. The first cavity 1326 can be configured to be offset from thehead component 1320. For example, a first cavity axis 1330 of the firstcavity 1326 can be offset by a first offset 1331 relative to a head axis1329 of the head component 1320 (see also FIGS. 37A-37E). The head axis1329 can be defined to pass through a center of the head component 1320,or a center of a plane defined by the outer rim 1324. The cavity axiscan be defined to pass through a center of the cavity 1326, or as anaxis equidistant from many, most, or all points on a surface definingthe cavity 1326 and perpendicular to a plane including the outer rim1324.

Referring further to FIGS. 36A-36F, the second insert component 1350includes an engagement member 1351, an insert body 1352, and a slotengagement feature 1353. The slot engagement feature 1353 extends from afirst end 1354 adjacent to the insert body 1352 to a second end 1355.The second insert component 1350 is similar to the insert component1140, except that the engagement member 1351 is configured to be alignedwith a center of the insert body 1352. For example, the engagementmember 1351 can define an engagement axis 1356 which passes through acenter of the engagement member 1351 (e.g., through a point equidistantfrom many, most, or all points on a side surface of the engagementmember 1351). The engagement axis 1356 can also pass through a center ofthe insert body 1352 (e.g., through a center of a surface of the insertbody 1352).

The insert body 1352 can define a height h₁₂. The height h₁₂ can be lessthan or equal to a height of the receiving wall 1328 of the headcomponent 1320, such that the insert body 1352 fits within the secondcavity 1327.

Referring further to FIGS. 37A-37E, various views and configurations ofthe humeral head implant system 1300 are shown according to anembodiment of the present disclosure. The humeral head implant system1300 is configured such that the head component 1320 (e.g., a surface ofthe head component 1320 defined by the outer rim 1324) contacts the basecomponent 1160 (e.g., a surface of the base component 1160 from whichthe slot 1164 extends). The head component 1320 may be seated flushagainst the base component 1160.

By including the first insert component 1340 and second insert component1350, the head component 1320 may be seated flush against the basecomponent 1160 independent of an orientation of the head component 1320relative to the base component 1160. For example, the head component1320 may be oriented at various angles about the head axis 1329 when thefirst insert component 1340 is received in the first cavity 1326. Thefirst insert component 1340 may be oriented at various angles when theengagement member 1351 is received in the first insert component 1340.Because the first insert component 1340 enables the head component 1320to be rotated about the second insert component 1350, the head component1320 may be flush against the base component 1160 at any angularorientation.

In some embodiments, the humeral head implant system 1300 is configuredto offset the head axis 1329 of the head component 1320 from a base axis1171 of the base component 1160. The offset between the head axis 1329and the base axis 1171 can be defined as a sum of the first offset 1331between the head axis 1329 and the cavity axis 1330 and a second offsetbetween a first insert axis 1343 of the first insert 1340 and a firstinsert cavity axis 1344 of the first insert 1340. When the first insertcomponent 1340 is received in the head component 1320, the first insertaxis 1343 may align with the cavity axis 1330. When the second insertcomponent 1350 is received in the first insert cavity 1342 of the firstinsert component 1340, the engagement axis 1356 may align with the firstinsert cavity axis 1344 of the first insert cavity 1342. When the secondinsert component 1350 is received by the base component 1160, theengagement axis 1356 may align with base axis 1171 of the base component1160.

C. Method of Performing Posterior Rotator Cuff Sparing TotalArthroplasty

Referring now to FIGS. 38A-38B, schematic diagrams of an exampleshoulder anatomy are illustrated. The shoulder anatomy includes therotator cuff, including the supraspinatus 1404 (which can abduct thehumerus), infraspinatus 1406 (which can externally rotate the humerus),teres minor 1408 (which can externally rotate the humerus), andsubscapularis 1409 (which can internally rotate the humerus). Theshoulder anatomy also includes acromion 1402, clavicle 1410,coraco-acromial ligament 1412, and greater tuberosity 1414 of thehumerus 1416. The coraco-acromial ligament 1412 defines subacromialspace 1414, in which bursa 1418 and supraspinatus 1404 are located. Thecoraco-acromial ligament 1412 connects to the acromion 1402 and coracoidprocess 1420 of scapula 1422. Long head of biceps 1428 tendon 1424 alsoconnects the humerus 1416 to scapula 1422. The shoulder anatomy alsoincludes gleno-humeral joint 1426, bursa 1428 between the acromion 1402and rotator cuff, and acromioclavicular joint 1430.

In existing solutions, shoulder arthroplasty can result in long recoverytimes due to how the rotator cuff is removed in order to perform theprocedure. The present disclosure relates to devices, systems, andmethods for improving shoulder arthroplasty while preventing damage tothe rotator cuff, such as by using instruments that can position thehumerus and glenoid at an accessible orientation for implantinstallation without cutting the rotator cuff. The traditional totalshoulder arthroplasty approach utilizes a subscapularis takedown viatenotomy, peel or lesser tuberosity osteotomy.

Total shoulder arthroplasty (TSA) has long been one of the moresuccessful procedures orthopaedic surgeons perform. Complicationsincluding subscapularis rupture, dysfunction and attenuation, infection,superior rotator cuff failure, and glenoid loosening remain issues.Subscapularis dysfunction and failure are the leading complications ofTSA, occurring in 11%-66% of patients. Surgical intervention forsubscapularis dysfunction is relatively rare, but frequently isunsuccessful. The standard anterior approach to the shoulder requiresdivision of the subscapularis tendon either through a tenotomy, peel, orlesser tuberosity osteotomy. It is accepted that the lesser tuberosityosteotomy and peel techniques are more resistant to subscapularisrupture, but chronic nerve denervation, weakness and tendon dysfunctionare still relatively common and long-lasting. Subscapularisinsufficiency may result in long term issues with glenoid loosening dueto increased forces on the cement-prosthesis interface. Efforts toreduce subscapularis-related complications and improve glenoid exposureled some surgeons to question traditional surgical techniques.

Referring to various embodiments of shoulder arthroplasty procedures infurther detail, a subscapularis split, rotator interval andsub-subscapularis approach can spare the rotator cuff and provideimproved functional outcomes for patients. Rotator cuff-sparing totalshoulder arthroplasty may improve post-operative pain, rehabilitationand subscapularis function and strength. A rotator cuff-sparingposterior approach to shoulder arthroplasty that utilizes the intervalbetween the teres minor and infraspinatus and an in-situ osteotomy isdescribed herein.

The posterior approach utilizes a split of the middle and posteriorheads of the deltoid and the internervous plane between the teres minorand infraspinatus. Because it avoids subscapularis and posterior rotatorcuff tendon release and repair, early active motion can be performed. Insome embodiments, benefits of this approach include avoidance ofsubscapularis dysfunction or rupture, improved access to the retrovertedglenoid, and the ability to perform posterior soft tissue balancing.Newer implants, including stemless humeral components have facilitatedthis approach for selected patients with reasonable proximal humeralbone. Additionally, this approach improves visualization of the humerusand glenoid over rotator interval and subscapularis-splittingapproaches.

In some embodiments, total shoulder arthroplasty can be performedthrough a variety of surgical approaches. The posterior approach isdescribed herein. The benefits of a posterior approach include improvedvisualization of the retroverted glenoid, the ability to performposterior soft tissue balancing, and the ability to protect theoverlying rotator cuff.

Typical surgical instruments can be used in this particular approach aswell as some specialized instruments shown in FIGS. 1-21. Several ofthese, such as those shown in the Figures, are specially designed toenhance the exposure in a posterior shoulder arthroplasty. The posteriorapproach can be performed using a stemless shoulder component.

Referring now to FIGS. 39A-39B and FIGS. 41A-41Z, a method 1500 ofperforming a posterior approach shoulder arthroplasty is shown accordingto various embodiments of the present disclosure. The method 1500 may beperformed by various entities, including a surgeon, technician, or othermedical professional, or a robotic surgical system. It will beappreciated that while at least some portions of the method 1500 may bedescribed in terms of sequential steps, various steps may be rearranged,modified, or omitted by those skilled in the art, such as for tailoringthe performance of the shoulder arthroplasty to particular patientneeds.

At 1505, a body 1800 of a patient may be oriented to provide appropriateaccess to the shoulder for a posterior approach. In some embodiments,the patient may be placed in a lateral position (e.g., as compared to ananterior approach, in which the patient is placed supine with an armboard at the side). Orienting the patient may include placing anaxillary roll. Orienting the patient may also include padding bonyprominences. In some embodiments, orienting the patient includesadducting an arm of the patient (e.g., an arm adjacent to the shoulderto be operated on) to be placed across the body, which can improveglenoid exposure. The arm may be maximally adducted. In someembodiments, the shoulder anatomy 1804 is labeled. For example, theposteriolateral corner 1806 of the acromion (e.g., acromion 1402) may bemarked using a marking pen. The humeral head 1808 may be outlined aswell.

At 1510, an incision is made, such as to expose or begin exposure of asurgical site or an implant site. The incision may be made from the armto the acromion 1402. For example, the incision may be made from the midposterior arm 1802′ to a point 1810 just above the axilla approximatelytwo to three centimeters posterior to the post lateral tip of theacromion 1402. In some embodiments, electrocautery is utilized (e.g.,along the incision) to coagulate any skin bleeders. In some embodiments,dissection is carried down through skin and subcutaneous tissues.

At 1515, the deltoid is exposed. For example, Gelpi retractors 1812 maybe placed, and Metzenbaum scissors 1814 may be used to expose aninferior aspect 1816 of the deltoid.

At 1520, the sub-deltoid space (e.g., a space under the deltoid relativeto a direction from which the deltoid is being accessed) is exposed. ARichardson retractor 1818 may be used to pull the deltoid moreproximally such that the sub-deltoid space 1820 is exposed.

At 1525, the posterior and middle heads of the deltoid may be dissected.For example, a finger can be used to bluntly dissect between theposterior and middle heads of the deltoid. In some embodiments,electrocautery is used to further this exposure. In some embodiments,using electrocautery may include applying the electrocautery at adistance from the axillary nerve (e.g., distally to the exposure) toavoid the axillary nerve.

At 1530, a subacromial space may be entered. For example, posteriorfascial bands 1822 across the rotator cuff may be incised to enter thesubacromial space. In some embodiments, posterior fascial bands may beincised without cutting through the rotator cuff as performed inanterior approach shoulder arthroplasty, which may help preserve therotator cuff and reduce the likelihood of and extent of post-operativerecovery necessary for the rotator cuff.

At 1535, the teres minor 1408 (which may be relatively inferior) and theinfraspinatus 1406 (which may be relatively superior) are identified.For example, the infraspinatus 1406 may be identified based on theinfraspinatus 1406 being relatively more muscular, while the teres minor1408 may be identified based on the teres minor having white fascialbands. In some embodiments, a tagging stitch 1824 may be applied to theinfraspinatus 1406 and the teres minor 1408.

At 1540, traction is applied to expose the capsule underlying therotator cuff. At 1545, the rotator cuff is taken laterally in a split tothe greater tuberosity. For example, the rotator cuff may berepositioned, or portions of the rotator cuff may be separated, withoutcutting through the rotator cuff (e.g., division of the subscapularistendon).

At 1550, exposure of the implant site is enhanced. For example, exposureof the capsule 1826 and rotator cuff can be enhanced. Retractors 1828(e.g., Army Navy retractors) may be placed superiorly and inferiorly toenhance the exposure of the capsule and rotator cuff.

At 1555, the capsule can be visualized; two retractors 1830 (e.g.,Hohmann retractors), one proximally and one distally, may be applied,such as to better expose the capsule.

At 1560, a capsulotomy is performed. Performing the capsulotomy mayinclude cutting into the capsule. In some embodiments, a T-shapedcapsulotomy is made from the lateral aspect of the greater tuberosity tothe glenoid.

At 1565, a superior capsule relieflet is taken. For example, a T-capsulefrom the T-shaped capsulotomy may be taken superiorly up and around thesuperior aspect of the shoulder. A tagging stitch may be placed into thesuperior capsule relieflet. In some embodiments, a T-shaped capsulotomy1832 may be made from the inferior aspect of the capsule. The T-shapedcapsulotomy from the inferior aspect of the capsule may be taken alongthe humeral neck or along the inferior humeral osteophytes. In someembodiments, a tagging stitch may be applied to the inferior capsulerelieflet such that traction can be performed.

At 1570, the superior aspect of the shoulder may be at least one ofexposed or protected. A retractor 1834 may be used to perform theexposure and/or protection. For example, a Crego retractor may be placedsuperiorly to expose and protect the superior aspect of the shoulder.

At 1575, a humeral osteotomy is performed. Performing the osteotomy mayinclude removing bone pieces in and around the humeral head to preparethe humeral head for an implant. In some embodiments, a guide 1836 isplaced such that version and angulation of the osteotomy (e.g., of thecut made to perform the osteotomy) may be assessed and more easilyperformed. The osteotomy can then be performed after guide placement. Insome embodiments, performing the osteotomy can include removing inferiorhumeral osteophytes 1838.

In some embodiments, performing the method 1500 can include exposing theglenoid, which may include one or more of the procedures described at1580-1585. At 1580, the arm 1802 may be adducted across the body. At1585, an anterior glenoid retractor 1840 may be placed. In someembodiments, the anterior glenoid retractor may be configured tofacilitate improved exposure once the surgeon goes to the anterioraspect of the shoulder. The anterior glenoid retractor may be relativelylarge (e.g., as compared to other retractors described herein).

At 1590, the glenoid is visualized from the anterior aspect 1800′ of thepatient. At 1595, a central aspect of the glenoid is marked, which canfacilitate further operations on the glenoid.

At 1600, the glenoid is reamed. In some embodiments, a drill 1842 isinserted into the glenoid 1844 such that a reamer 1846 may be placed.Glenoid reaming can be performed to prepare the glenoid to receive animplant. Glenoid reaming can be performed to shape the glenoid into anappropriate geometry to facilitate desired kinematics for movement ofthe arm relative to the shoulder after the procedure is completed.

At 1605, a glenoid guide 1848 is placed, which can help guide insertionand alignment of implants. At 1610, a first glenoid drill can be placed,followed by a peg in the inferior aspect of the glenoid, and a secondglenoid drill can be placed superiorly (e.g., in the superior aspect ofthe glenoid; superior to the first glenoid drill). At 1615, a broach1850 is placed and impacted in position.

At 1620, once the broach is in position, a trial implant 1852 is placed.At 1825, the trial 1852 implant is removed (e.g., based on the trialimplant 1852 position satisfying an implant position condition, such asfor facilitating appropriate or desired arm movement). Glenoidcementation techniques can be used to prepare the implant site forimplantation. In some embodiments, thrombin soaked sponges are placed.At 1630, cement is placed to secure the implant site. At 1635, theglenoid 1854 is impacted in position. In some embodiments, excess cementmay be removed (e.g., using a Freer elevator).

At 1640, the humerus is exposed. In some embodiments, the humerus isexposed by one or more of adduction, internal rotation, and forwardflexion of the arm (or the humerus at the shoulder), such as to returnto the posterior aspect of the implant site 1800.

At 1645, a retractor is placed in an interval of the rotator cuff (e.g.,where the rotator cuff is split). In some embodiments, the retractor maybe placed below the calcar. At 1650, an additional retractor (e.g.,Richardson retractor) is placed more laterally than the retractor placedin the interval, such as to expose the cut of the humeral head.

At 1655, a trial humeral head component 1856 is placed. In someembodiments, a pin 1858 is placed through a central aspect of the trialhumeral head component 1856, such as to verify that a position of thehumerus (or of the trial humeral head component on the humerus) isaccurate. At 1660, a surface of the humeral osteotomy is sized (e.g.,after removing the trial humeral head component 1856). The trial humeralhead component 1856 can be removed and the humeral osteotomy surfacesized.

At 1665, a baseplate 1860 can be secured to the glenoid. For example,the baseplate 1860 can be inserted and tapped into position. Thebaseplate 1860 may be selected based upon anatomical or kinematicrequirements for the shoulder of the patient.

At 1670, the trial humeral head component 1856 is placed into position.In some embodiments, placing the trial humeral head component 1856includes placing the trial humeral head component 1856 based on adesired spatial relationship between the greater tuberosity and thehumeral head. An imaging device may be used to identify the spatialrelationship between the greater tuberosity and the humeral head. Forexample, a mini C-arm can be used to identify the accuracy of theplacement of the trial humeral head component along the glenoid (e.g.,based on receiving image data of the implant site and trial humeral headcomponent 1856 from the mini C-arm). In some embodiments, the positionof the trial humeral head component 1856 can be modified based on theaccuracy of the placement to achieve the desired spatial relationship.At 1675, the shoulder is reduced. For example, the humerus can bealigned in a desired anatomical relationship (e.g., orientation)relative to the glenoid.

At 1680, the trial humeral head component is removed and the realhumeral baseplate 1862 is impacted into position. In some embodiments,the baseplate 1862 is impacted to be flush with the cut surface of thehumeral head. At 1685, an inserter is removed. In some embodiments, thebaseplate 1862 is cleaned. The real humeral implant 1864 is placed(e.g., based on the range of motion and alignment of the shouldermeeting corresponding criteria). In some embodiments, placing the realhumeral implant 1864 can include securing the real humeral implant 1864to the real humeral baseplate 1862 via a Morse taper. In someembodiments, placing the real humeral implant 1864 includes impactingthe real humeral implant into position 1864 and checking the Morse taperto confirm that the real humeral implant 1864 is engaged to the realhumeral baseplate 1862. The shoulder can be reduced. In someembodiments, the accuracy of the cut is assessed, such as by using animaging device such as the mini C-arm.

At 1690, the T-shaped capsulotomy is repaired. In some embodiments, theT-shaped capsulotomy is repaired using at least one figure of eightstitches. The capsule and posterior rotator cuff are repaired. In someembodiments, the deltoid is repaired. The capsule is repaired to therotator cuff. In some embodiments, the T-shaped capsulotomy can easilybe visualized and the capsule is repaired to the lateral portion of therotator cuff (e.g., based on the visualization). In some embodiments,the capsule can be imbricated, such as to improve soft tissue balancingof the posterior aspect of the humerus. In some embodiments, figure ofeight stitches are placed in the capsule in order to improve thestrength of the repair. After figure of eight stitches are placed intothe capsule and the capsule is fully repaired, the posterior rotatorcuff split between the teres minor and infraspinatus can be repaired.For example, a running figure of eight rotator cuff stitch is placed. Insome embodiments (e.g., if there is demonstration of preoperativesubluxation of the posterior shoulder), an imbrication stitch here canbe performed. As compared to an anterior approach, in which asubscapularis takedown may require significantly more complicatedrotator cuff repair procedures, and may result in chronic nervedenervation, weakness, tendon dysfunction, or glenoid loosening, theposterior approach described herein can facilitate improved shoulderrecovery.

In some embodiments, post-operatively, the patient is allowed to beplaced in a sling for one to two weeks but active motion may be utilizedat any time when pain allows. Posterior joint stabilization precautionscan be put in place for a total of six weeks. For example, the acombination of adduction and forward flexion with a forced posteriorload may be restricted. After the capsule and rotator cuff are closed,range of motion may be assessed. It will be appreciated that the patientcan have near full range of motion and forward flection and fullabduction and external rotation of 90 degrees adduction and an extremelystable shoulder.

Referring back to FIGS. 40A-40C, various embodiments of posteriorapproach total shoulder arthroplasty are illustrated. As shown in FIG.40A, an implant site 1700 (e.g., similar to the shoulder anatomiesdescribed with reference to FIGS. 38A-38B) including a capsule 1701 canbe manipulated with a retractor 1702 (e.g., Richardson retractor) toimprove exposure of the implant site 1700, while a humeral head implant1703 can be impacted in position. As shown in FIG. 40B, retractors 1704(e.g., Hohmann retractors) can be placed proximally and distally tobetter expose the capsule. As shown in FIG. 40C, an implant 1705 can beplaced at the implant site 1700.

What is claimed is:
 1. A humeral head implant system, comprising: a head component including a first convex articulating surface configured to articulate in a shoulder cavity, a second bottom surface extending from a rim of the first convex articulating surface, a first cavity extending into the head component from the second bottom surface, and a second cavity extending into the head component from the first cavity, the second cavity defining a central second cavity axis, the head component defining a head axis extending through a center of the first convex articulating surface, the head axis spaced from and parallel to the second cavity axis; a base component defining a base cavity extending into the base component, the base component including a proximal face sized and shaped to be received within the first cavity of the head component so that the proximal face of the base component sits flush with the head component, the base component further including a plurality of legs adapted to anchor the base component into a humerus; and an insert member including a first insert portion and a second insert portion, the first insert portion having a proximal end sized to be received within the second cavity of the head component, the second insert portion having a distal end sized to be received within the base cavity of the base component, the second insert portion defining an insert axis configured to be spaced from and parallel to the second cavity axis when the proximal end of the first insert portion is received within the second cavity of the head component and the distal end of the second insert portion is received within the base cavity of the base component.
 2. The humeral head implant system of claim 1, wherein the head component is configured to be rotated about the second cavity axis relative to the first insert portion to adjust a position of a center of the head component relative to the first insert portion.
 3. The humeral head implant system of claim 1, wherein the first insert portion is configured to form a Morse taper with the second cavity.
 4. The humeral head implant system of claim 1, wherein the head component is sized to fit into an implant site targeted for total shoulder arthroplasty.
 5. The humeral head implant system of claim 1, wherein the base component includes an extension extending distally away from the proximal face of the base component, the plurality of legs extending radially from the extension.
 6. The humeral head implant system of claim 5, wherein the plurality of legs includes a first leg extending a first length from the extension, and two legs extending a second length from the extension.
 7. The humeral head implant system of claim 5, wherein a distal end of the extension defines a distal end of the base component.
 8. The humeral head implant system of claim 7, wherein the distal end of the extension defines a cylindrical channel.
 9. The humeral head implant system of claim 8, wherein the cylindrical channel opens to the distal end of the base component.
 10. The humeral head implant system of claim 7, wherein a distal end of the plurality of legs is positioned adjacent the distal end of the base component.
 11. The humeral head implant system of claim 5, wherein a spacing between each adjacent pair of the plurality of legs is equal.
 12. The humeral head implant system of claim 5, wherein each of the plurality of legs includes a first side edge extending distally, and a bottom edge extending radially inwardly from a distal end of the first side edge toward the extension. 